In-vitro metabolism of a mixture of atrazine and simazine by the soluble fraction (105000g) from goose, pig and sheep liver-homogenates

1979 ◽  
Vol 10 (6) ◽  
pp. 460-466 ◽  
Author(s):  
Shahamat U. Khan ◽  
Thomas S. Foster ◽  
M. Humayoun Akhtar
Keyword(s):  
Soluble Fraction ◽  
In Vitro Metabolism ◽  
Sheep Liver ◽  
Liver Homogenates

The in vitro metabolism of Eulan WA New by liver homogenates from freshwater fish

1986 ◽  
Vol 84 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Andrew Machon ◽  
Michael J. North ◽  
Nicholas C. Price ◽  
David E. Wells
Keyword(s):  
Freshwater Fish ◽  
In Vitro Metabolism ◽  
Liver Homogenates

SOME BIOCHEMICAL EFFECTS OF SPORIDESMIN

1965 ◽  
Vol 43 (7) ◽  
pp. 881-888 ◽  
Author(s):  
D. E. Wright ◽  
I. T. Forrester
Keyword(s):  
Guinea Pig ◽  
Succinate Oxidation ◽  
Biochemical Effects ◽  
Sheep Liver ◽  
Liver Homogenates ◽  
Nicotinamide Coenzymes

Sporidesmin inhibits in vitro the respiration of guinea pig and sheep liver homogenates in the presence of substrates which require nicotinamide coenzymes for their oxidation. Succinate oxidation was far less sensitive. Similar results were found with mitochondria.Slight swelling and release of 260 mμ absorbing compounds from mitochondria incubated in the presence of sporidesmin were observed. These results are discussed in relation to those reported elsewhere.

The effects of cofactor and species differences on the in vitro metabolism of propiophenone and phenylacetone

1981 ◽  
Vol 59 (2) ◽  
pp. 195-201 ◽  
Author(s):  
R. T. Coutts ◽  
D. R. Prelusky ◽  
G. R. Jones
Keyword(s):  
Rat Liver ◽  
In Vitro Metabolism ◽  
Metabolic Route ◽  
Liver Preparation ◽  
Carbonyl Reduction ◽  
Alcohol Dehydrogenation ◽  
Liver Homogenates ◽  
A Minor ◽  
Minor Extent

In vitro metabolism of the aromatic ketone propiophenone and its nonaromatic isomer phenylacetone was studied using fortified 12 000 × g supernatants of liver homogenates from rat and rabbit. Reduction to the corresponding alcohols was the major metabolic route observed, although aliphatic C-hydroxylation and alcohol dehydrogenation also occurred. Marked differences were observed in the amounts of carbonyl reduction of the substrates, which was dependant on the species as well as the cofactor employed. Using rat liver preparation, phenylacetone was reduced to 1-phenyl-2-propanol much more efficiently with an NADH-fortified system than when NADPH was used whereas in rabbit, extensive reduction occurred in the presence of either cofactor. Reduction of propiophenone to 1-phenyl-1-propanol by rat liver preparation was slightly greater in the presence of NADH than with NADPH; the converse was observed in rabbit.Aliphatic hydroxylation of propiophenone to 2-hydroxy-1-phenyl-1-propamine was also a significant metabolic pathway in both species, with NADPH being the more efficient cofactor, but C-1 hydroxylation of phenylacetone to 1-hydroxy-1-phenyl-2-propanone occurred only to a minor extent. Small amounts of 1-phenyl-1,2-propanedione, as well as both erythro and threo isomers of 1-phenyl-1,2-propanediol, were also identified as metabolites in both species. Similar metabolic studies were carried out on the alcohols 1-phenyl-1-propanol and 1-phenyl-2-propanol and again the nature and quantities of metabolites isolated showed both species and cofactor dependancies.

scholarly journals The Metabolism of Gammekane and Related Compounds

2021 ◽  
Author(s):  
◽  
Alan Geoffrey Clark
Keyword(s):  
Liver Enzyme ◽  
Gel Filtration ◽  
Dicarboxylic Acids ◽  
In Vitro Metabolism ◽  
Enzyme Preparations ◽  
Sheep Liver ◽  
Lysine Residues ◽  
Complete Exclusion

<p>1. A detailed kinetic study has been made of the glutathione S-aryl-transferases from the New Zealand grass grub (Costelytra zealandica) and from sheep liver. The insect enzyme behaves in accordance with a Michaelis-Menten model for two-substrate enzymes. It is inhibited by the sulphonphthaleins, phthaleins, fluoresceins and dicarboxylic acids competing with glutathione, while the sheep-liver enzyme is not susceptible to this type of inhibition. From this, and other data obtained from a study of the variation of kinetics with pH, it is proposed that two basic groups (possibly lysine residues) are involved in binding of glutathione to the insect enzyme, while only one such group appears in the sheep-liver enzyme. Binding of the aromatic substrate to the enzyme in both species may involve a histidine residue. 2. The accumulation of little significant radioactivity in diluant 2gamma-pentachlorocyclohexene (gamma-PCCH) during the in vitro metabolism of [14C]gamma-hexachlorohexane (gamma-HCH) suggests that the PCCH's are not formed as free intermediates during the metabolism of the HCH's. However, certain ambiguities introduced with the experimental techniques used preclude the complete exclusion of this possibility. 3. gamma-HCH, gamma-PCCH and delta-PCCH metabolized in vivo by M.domestica and C.zealandica and in vitro by preparations from both species, all produce as the principal metabolite a glutathione conjugate with chromatographic properties identical with those of authentic S-(2,4-dichlorophenyl)glutathione. There is, however some doubt as to the identity of the S-substituent moiety. 4. The in vitro metabolism of gamma-HCH and delta-PCCH is glutathione-dependent and is inhibited by various phthaleins and sulphonphthaleins. The in vivo metabolism of delta-PCCH in C.zealandica is profoundly affected by this type of compound, but its effects on the rate of metabolism in vivo of delata-HCH in M.domestica and C.zealandica are only marginal. 5. The enzyme concerned in the metabolism of delta-PCCH has been shown to differ from aryltransferase in M.domestica and C.zealandica by gel filtration techniques and by differences in activity in different enzyme preparations. The delta-PCCH-metabolising activity appears to be associated with a DDT dehydrochlorinase activity. In M.domestica, there appears to be, in addition, a second DDT dehydrochlorinase with only a low cross-specificity towards delta-PCCH.</p>

scholarly journals The Metabolism of Gammekane and Related Compounds

2021 ◽  
Author(s):  
◽  
Alan Geoffrey Clark
Keyword(s):  
Liver Enzyme ◽  
Gel Filtration ◽  
Dicarboxylic Acids ◽  
In Vitro Metabolism ◽  
Enzyme Preparations ◽  
Sheep Liver ◽  
Lysine Residues ◽  
Complete Exclusion

<p>1. A detailed kinetic study has been made of the glutathione S-aryl-transferases from the New Zealand grass grub (Costelytra zealandica) and from sheep liver. The insect enzyme behaves in accordance with a Michaelis-Menten model for two-substrate enzymes. It is inhibited by the sulphonphthaleins, phthaleins, fluoresceins and dicarboxylic acids competing with glutathione, while the sheep-liver enzyme is not susceptible to this type of inhibition. From this, and other data obtained from a study of the variation of kinetics with pH, it is proposed that two basic groups (possibly lysine residues) are involved in binding of glutathione to the insect enzyme, while only one such group appears in the sheep-liver enzyme. Binding of the aromatic substrate to the enzyme in both species may involve a histidine residue. 2. The accumulation of little significant radioactivity in diluant 2gamma-pentachlorocyclohexene (gamma-PCCH) during the in vitro metabolism of [14C]gamma-hexachlorohexane (gamma-HCH) suggests that the PCCH's are not formed as free intermediates during the metabolism of the HCH's. However, certain ambiguities introduced with the experimental techniques used preclude the complete exclusion of this possibility. 3. gamma-HCH, gamma-PCCH and delta-PCCH metabolized in vivo by M.domestica and C.zealandica and in vitro by preparations from both species, all produce as the principal metabolite a glutathione conjugate with chromatographic properties identical with those of authentic S-(2,4-dichlorophenyl)glutathione. There is, however some doubt as to the identity of the S-substituent moiety. 4. The in vitro metabolism of gamma-HCH and delta-PCCH is glutathione-dependent and is inhibited by various phthaleins and sulphonphthaleins. The in vivo metabolism of delta-PCCH in C.zealandica is profoundly affected by this type of compound, but its effects on the rate of metabolism in vivo of delata-HCH in M.domestica and C.zealandica are only marginal. 5. The enzyme concerned in the metabolism of delta-PCCH has been shown to differ from aryltransferase in M.domestica and C.zealandica by gel filtration techniques and by differences in activity in different enzyme preparations. The delta-PCCH-metabolising activity appears to be associated with a DDT dehydrochlorinase activity. In M.domestica, there appears to be, in addition, a second DDT dehydrochlorinase with only a low cross-specificity towards delta-PCCH.</p>

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